Method for coding and decoding 3D data implemented as a mesh model

Abstract

A method for coding three-dimensional (3D) data, and more particularly for coding geometry data included in the 3D data. The method includes: generating a bounding box including a vertex of the 3D data based on information included in the geometry data; dividing the bounding box into a plurality of partitions having an equal size; identifying a number of vertices included in each divided partition; appointing a divided partition as a leaf cell based on the identified number of vertices; and coding the geometry data using information on the dividing of the bounding box, information on vertices included in each divided partition, and information indicating the position of a vertex included in the leaf cell, when a divided partition is subdivided.

1. A method for coding and transmitting geometry data included in three-dimensional (3D) data expressed by a mesh model in a transmitting apparatus, the method comprising:
 generating, by a processor, a bounding box including at least one vertex of the 3D data based on information included in the geometry data; 
 dividing the bounding box into a plurality of partitions having an equal size; 
 identifying a number of vertices included in each of the divided partitions; 
 appointing a divided partition as a leaf cell based on the identified number of vertices included in the divided partition; 
 coding, by an encoder, the geometry data using information on the dividing of the bounding box, information on the vertices included in each of the divided partitions, and information indicating a position of a vertex included in the leaf cell; and 
 transmitting, by a transmitter, the encoded geometry data to a receiving device. 
 
     
     
       2. The method of  claim 1 , further comprising:
 subdividing a divided partition into a plurality of sub-partitions based on the identified number of vertices included in the divided partition; 
 identifying a number of vertices included in each of the subdivided sub-partitions; and 
 appointing a subdivided sub-partition as a leaf cell based on the identified number of vertices included in the subdivided sub-partition. 
 
     
     
       3. The method of  claim 2 , wherein subdividing the divided partition is repeated a predetermined number of times. 
     
     
       4. The method of  claim 1 , wherein, when the divided partition includes less than two vertices, the divided partition is appointed as the leaf cell. 
     
     
       5. The method of  claim 1 , wherein the geometry data is coded using a cell's level, which indicates a division rank, as a context. 
     
     
       6. The method of  claim 1 , wherein the information on the division of the bounding box includes information indicating a level generated according to a step-by-step division of the bounding box. 
     
     
       7. The method of  claim 1 , wherein the information on the vertices included in each of the divided partitions includes information indicating if each of the divided partitions includes vertices greater than a predetermined number of vertices, or information indicating if each of the divided partitions includes no vertex. 
     
     
       8. The method of  claim 1 , wherein the information indicating the position of the vertex included in the leaf cell includes information indicating a partition in which the vertex included in the leaf cell is positioned among partitions divided at a lower level. 
     
     
       9. The method of  claim 1 , wherein dividing the bounding box comprises dividing the bounding box by applying an octree to the bounding box. 
     
     
       10. The method of  claim 1 , wherein identifying the number of vertices included in each of the divided partitions comprises determining whether each of the divided partitions includes vertices greater than a predetermined number of vertices. 
     
     
       11. A method for receiving and decoding geometry data included in three-dimensional (3D) data expressed by a mesh model by a receiving apparatus, the method comprising:
 receiving, by the receiving apparatus, encoded geometry data transmitted from an encoding apparatus; 
 decoding, by a decoder, a bounding box generated during a coding process of the geometry data; 
 identifying, by a processor, information on divisions of the bounding box; 
 identifying whether a specific partition of the bounding box has been divided into a lower level or corresponds to a leaf cell; 
 subdividing the specific partition that has been divided into the lower level; 
 restoring a vertex included in the leaf cell, based on information indicating a position of the vertex included in the leaf cell; and 
 restoring the geometry data including the information on the position of the vertex based on information on a vertex included in each of divided partitions of the bounding box and a position of each the divided partitions. 
 
     
     
       12. The method of  claim 11 , wherein a reference point of either the leaf cell or a partition divided up to a lowest level is appointed as a vertex position. 
     
     
       13. The method of  claim 11 , further comprising:
 acquiring context information on a level of a partition, which is been inserted to the geometry data in the coding process; and 
 restoring the geometry data based on the context information. 
 
     
     
       14. A method for coding and transmitting geometry data that is included in three-dimensional (3D) data expressed by a mesh model by a transmitting apparatus, and receiving and decoding the coded geometry data based on the coding method by a receiving apparatus, the coding method comprising:
 generating, by a processor of the transmitting apparatus, a bounding box including at least one vertex of the 3D data based on information included in the geometry data; 
 dividing the bounding box into a plurality of partitions having an equal size; 
 identifying a number of vertices included in each the divided partitions; 
 subdividing or appointing a divided partition as a leaf cell based on the identified number of vertices included in the divided partition; and 
 coding the geometry data using information on the dividing of the bounding box, information on the vertices included in each of the divided partitions, and information indicating a position of a vertex included in the leaf cell, 
 wherein the decoding method comprises: 
 decoding the bounding box generated in the coding process; 
 identifying, by a processor of the receiving apparatus, the information on the dividing of the bounding box; 
 identifying whether a specific partition has been divided into a lower level or corresponds to a leaf cell; 
 subdividing the specific partition that has been divided into the lower level; 
 restoring a vertex included in the leaf cell based on information indicating the position of the vertex included in the leaf cell; and 
 restoring the geometry data including the information on the position of the vertex based on information on a vertex included in each of the divided partitions and a position of each of the divided partitions.